Chronic obstructive pulmonary disease (COPD) is a major public health problem and is the fourth leading cause of death in the United States. Despite pharmacologic and surgical therapy, COPD continues to cause considerable morbidity and mortality and is the only major disease among the top ten that continues to increase in prevalence. Novel and inexpensive interventions that can improve symptoms, health-related quality-of-life, functional capacity, and potentially modify disease progression are needed. Tai chi is a popular mind-body exercise that combines gentle physical activity, self awareness, and relaxation with slow mind-body breathing. It may be particularly suited to deconditioned individuals with COPD, who suffer from limited exercise tolerance and shortness of breath on exertion, and it integrates multiple components relevant to COPD management, including low-intensity aerobic exercise, stress management and slow mind-body breathing training. In this application, we propose a 3-arm randomized controlled trial (N=102) to evaluate the benefits of tai chi exercise (which includes mind-body breathing) versus seated mind-body breathing alone (an isolated, key component of the comprehensive tai chi program) versus education control. This design will allow us to examine the individual efficacy of each mind-body intervention on clinical outcomes in COPD, but will also allow clinical and physiological comparisons between the two interventions, providing insight into the components and mechanisms of mind-body therapies. Patients with COPD (Global Obstructive Lung Disease stages 1-3 with symptoms of dyspnea) will be recruited from outpatient primary care and pulmonary clinics. Our primary aim will be to examine the effects of tai chi and mind-body breathing on quality-of-life and exercise capacity in this population. Secondary aims will further explore the effects on clinical symptoms, psychosocial indices, cardiopulmonary function, strength and flexibility, biomarkers of systemic inflammation, and autonomic activity. The results of our proposed research will help inform clinical treatment of COPD, and further our mechanistic understanding of mind-body exercises and the role of slow, mind-body breathing.